22 



TEMPERATURE FLUCTUATIONS IN THE HUMAN BODY. 



To prevent cooling by evaporation from the surface, the water in the flask 

 was at first covered by a thin film of oil; but this necessitated such an elabo- 

 rate arrangement to protect the rubber tubing that the oil is now omitted, 

 with equally satisfactory results. The performance of the constant-tempora- 

 ture oven has proved very satisfactory, the temperature within the flask 

 frequently not changing more than 0.01 C. in an hour. 



CALIBRATION OF MERCURY THERMOMETERS. 



The following is an abstract of the calibrations of the various thermometers 

 used in the work, as given by the Physikalisch-Technische Reichsanstalt. 

 In the case of the Beckmann thermometers, data are given showing how the 

 constant K, previously mentioned, 1 is determined. The tables of corrections 

 for variations in caliber have been omitted in the Beckmann calibrations, but 

 a statement is made regarding the maximum value of the correction. 



Beckmann Thermometer PTR 40724. 



Since the thermometer is to be used at temperatures of 37 to 42 C, an 

 interpolation has been made in the above table, giving as the corrected value 

 of a scale division, 



1 .005 + [(37 - 30) -h (40 - 30) ] (1 .009 - 1 .005) = 1 .008 

 No caliber correction greater than 0.005 C. is given, so that for readings 

 only to 0.01 C, this correction is negligible. 



Beckmann Thermometer PTR 40723. 



This thermometer is to be used in calibrating at temperatures of 34 to 39 C. 



The corrected value of a scale division is therefore: 



1.007+ [(34 30)^(40-30)] (1.011-1.007) = 1.009 



No caliber correction greater than 0.005 C. is given. 



Richtcr Thermometer PTR 32689. 



Range 34-44 C, graduated in 0.01 C. Without sensible error throughout, 

 i. e., no correction so great as 0.005 C. 



In calibrating a Beckmann thermometer in this laboratory, its zero point 



was determined roughly, and then the thermometer was set by trial until the 



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